Semen analysis with regard to sperm number, sperm morphology and functional aspects

Abstract

The new World Health Organization (WHO) Manual for Semen Analysis contains several improvements. One is that the 20 million spermatozoa per mL paradigm has been ousted in favour of proper calculations of lower reference limits for semen from men, whose partners had a time-to-pregnancy of 12 months or less. The recommendation to grade the progressive motility as described in the third and fourth editions of the WHO manual was not evidence-based, and WHO was therefore motivated to abandon it. However, the new recommendation is not evidence-based either, and it is difficult to understand the rational for the new assessment. It may have been a compromise to avoid returning to the rather robust system recommended in the first edition (1980). The unconditional recommendation of the 'Tygerberg strict criteria' is not evidence-based, and seems to be the result of an unfortunate bias in the composition of the Committee in favour of individuals known to support the 'strict criteria' method. This recommendation will have negative effects on the development of andrology as a scientific field. Given the importance of the WHO manual, it is unfortunate that the recommendations for such important variables, as motility and morphology, lack evidence-based support.

Semen analysis and sperm function testing

“…14 Nonetheless, there is still scepticism about certain aspects of the new WHO manual. 15 The criticism by Eliasson 15 is mainly aimed at the recommendations for the evaluation of progressive motility and sperm morphology. According to Eliasson, 15 these recommendations are not evidence-based, which is true regarding progressive motility, but this assertion is unfounded for sperm morphology evaluation.…”

“…15 The criticism by Eliasson 15 is mainly aimed at the recommendations for the evaluation of progressive motility and sperm morphology. According to Eliasson, 15 these recommendations are not evidence-based, which is true regarding progressive motility, but this assertion is unfounded for sperm morphology evaluation. 4 Recent publications comparing sperm morphology cutoff values with in vitro and in vivo pregnancy results in infertile populations or socalled fertile and subfertile populations are in close agreement with the WHO 2010 values.…”

New WHO-reference limits—revolution or storm in a teapot?

“…Is it really sufficient to focus on spermatozoa with an 'ideal' morphology? [6][7][8] Clinical practice shows that patients with a percentage of at least 4-5% of ideally shaped spermatozoa do not show 95-96% of malformed or disturbed, non-functioning spermatozoa, but in the majority of cases have a reasonable number of spermatozoa with only slight aberrations and preserved fertilizing potential. 6,9 Reconsidering the original paper on the hemizona assay, there are many spermatozoa bound to the zona pellucida that do not meet strict criteria but show slight hyperelongations of the post-acrosomal region of the head.…”

“…9,11 Only focusing on the low values of morphologically normal spermatozoa, by using the strict categorisation, raises the question of its relevance. 7,8 There is a need to have precise criteria for defining ideal morphology, 12,13 but one should also note the continuum of shapes and sizes of sperm cells. Otherwise, much confusion will be caused in the future.…”

“…In line with this perspective, the investigation and treatment should not focus on unspecific symptoms but on any potential underlying disorder, thus reducing or even eliminating the contribution of the male partner to couple subfertility. 7 …”